US3733551A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency stabilization apparatus and method
Assignee: Microlab FXR LLC
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Filing: 1971-03-26
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Granted: 1973-05-15
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Expires: 1991-03-26
Abstract
Abstract A frequency stabilization system for stabilizing the frequency of a transmitter of the type comprising an oscillator having an active element, the resonant frequency of which varies as a function of at least the resistance of the element and the difference between a biasing signal and the threshold voltage of the element wherein the transmitter includes control means which is responsive to a control signal for producing the biasing signal and a lead connecting the control means with the element. The system includes first signal means for producing a signal which is proportional to the difference between the biasing signal and the threshold voltage. The first signal means is connected to the element so that a second signal is developed across the element in response to the application of the first signal thereto. The second signal is sensed by sensing means and is applied to one input of a differential amplifier, the other input of which is connected to a reference source. The output of the differential amplifier is connected to the control means so that the differential amplifier produces a control signal which is dependent upon the difference between the sensed second signal and the reference signal thereby to stabilize the frequency of the oscillator. A transmission system employing the frequency stabilization system and the method of frequency stabilizing the system are also disclosed.
Inventors
- 👤 H Augenblick
- 👤 L Eastman
- 👤 R Keller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:03
CPC Classifications
H; H03; H03B; H03B9/00; H03B9/12
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
217 words
A frequency stabilization system for stabilizing the frequency of a transmitter of the type comprising an oscillator having an active element the resonant frequency of which varies as a function of at least the resistance of said element and the value of a biasing signal applied to said element, control means responsive to a control signal for producing said biasing signal the value of which is dependent on the value of said control signal, and a lead connecting said control means with said element; said system comprising first signal means adapted to be connected to said element for producing a first signal which is proportional to said biasing signal whereby a second signal is developed across said element in response to the application of said first signal thereto from said first signal means, switch means having an input portion connected to said element and being selectively operable to connect said input with an output portion whereby said second signal appears at said output portion, a reference signal source, and comparing means connected to said reference signal source and the output portion of said switch means and adapted to be connected to said control means for comparing said second and reference signals to produce said control signal in accordance with the difference between said second and reference signals.
Claim 2
Dependent Claim
217 words
A frequency stabilization system for stabilizing the frequency of a transmitter of the type comprising an oscillator having an active element the resonant frequency of which varies as a function of at least the resistance of said element and the value of a biasing signal applied to said element, control means responsive to a control signal for producing said biasing signal the value of which is dependent on the value of said control signal, and a lead connecting said control means with said element; said system comprising first signal means adapted to be connected to said element for producing a first signal which is proportional to said biasing signal whereby a second signal is developed across said element in response to the application of said first signal thereto from said first signal means, switch means having an input portion connected to said element and being selectively operable to connect said input with an output portion whereby said second signal appears at said output portion, a reference signal source, and comparing means connected to said reference signal source and the output portion of said switch means and adapted to be connected to said control means for comparing said second and reference signals to produce said control signal in accordance with the difference between said second and reference signals.
Claim 3
Dependent Claim
20 words
A frequency stabilization system as in claim 1, and reference varying means for varying the value of said reference signal.
Claim 4
Dependent Claim
73 words
A frequency stabilization system as in claim 1, in which said oscillator includes a parasitic resistance, and a resistor adapted to be connected in series with said element and having a value substantially equal to the value of said parasitic resistance, said switch means including lead means for connecting said switch means across the series circuit of said element and said resistor whereby said second signal includes the voltage drop across said resistor.
Claim 5
Dependent Claim
17 words
A frequency stabilization system as in claim 1, in which said comparing means comprises a differential amplifier.
Claim 6
Dependent Claim
137 words
A frequency stabilization system as in claim 1, in which said element has a threshold voltage and the resonant frequency of said element is proportional to the difference between the value of said biasing signal and said threshold voltage, said control means including a modulator for applying said biasing signal to said element, and a power source connected to said comparing means and responsive to said control signal for applying an energizing signal to said modulator which is proportional to said biasing signal; said first signal means comprising a source of potential connected to said element for producing a voltage proportional to the negative magnitude of said threshold voltage, and a lead for connecting the power source with said element whereby said first signal is proportional to the difference between the biasing signal and said threshold voltage.
Claim 7
Dependent Claim
50 words
A frequency stabilization system as in claim 3, in which said second signal is a DC signal, and said switch means is connected to said control means and is responsive to the absence of said biasing signal for passing only said second signal from the input to the output portion.
Claim 8
Dependent Claim
67 words
A frequency stabilization system as in claim 3, in which said second signal is an AC signal, and said switch means is connected to said control means and is responsive to the absence of said biasing signal for passing only said second signal from the input to the output portion, and said reference signal source comprises an AC source having the same frequency as said AC signal.
Claim 9
Dependent Claim
120 words
A frequency stabilization system as in claim 1, in which said element has a threshold voltage and the resonant frequency of said element is proportional to the difference between the value of said biasing signal and said threshold voltage, said control means including a modulator for applying said biasing signal to said element, and a power source connected to said comparing means and responsive to said control signal for applying an energizing signal to said modulator which is proportional to said biasing signal; said first signal means comprising a source of potential connected to said element for producing a voltage proportional to the negative magnitude of said threshold voltage, and a lead for connecting the comparing means with said element.
Claim 10
Dependent Claim
25 words
A frequency stabilization system as in claim 1, and clipping means connected to said control means for clipping the biasing signal above a preselected level.
Claim 11
Dependent Claim
51 words
A frequency stabilization system as in claim 9, in which said clipping means comprises a unidirectional current conducting device connected to the output terminals of said control means, and source means for biasing said unidirectional current conducting device to conduct current only when said biasing signal is above said preselected level.
Claim 12
Dependent Claim
45 words
A frequency stabilization system as in claim 1, in which the resistance of said element changes during the application of said biasing signal thereto, and predistortion means connected to said element for distorting said biasing signal in inverse relationship to the change in said resistance.
Claim 13
Dependent Claim
226 words
A frequency stabilized transmission apparatus comprising, in combination: an oscillator having an oscillating element the resonant frequency of which varies as a function of at least the resistance of said element and the value of a modulating signal applied to said element, a modulator connected to said oscillator for producing said modulating signal in response to an input signal, signal generator means connected to said modulator for generating said input signal in response to a control signal whereby the value of said input signal is dependent on the value of said control signal, and frequency stabilization means for stabilizing the frequency of operation of said oscillator; said frequency stabilization means comprising first signal producing means connected to said element for applying a first signal to said element which is proportional to said modulating signal whereby a second signal is developed across said element in response to the application of said first signal thereto, switch means having an input portion connected to said element and being selectively operable to connect said input portion with an output portion whereby said second signal appears at said output portion, a reference signal source, and comparing means connected to said signal generating means, the output portion of said switch means and said reference signal source for producing said control signal in accordance with the difference between said second and reference signals.
Claim 14
Dependent Claim
226 words
A frequency stabilized transmission apparatus comprising, in combination: an oscillator having an oscillating element the resonant frequency of which varies as a function of at least the resistance of said element and the value of a modulating signal applied to said element, a modulator connected to said oscillator for producing said modulating signal in response to an input signal, signal generator means connected to said modulator for generating said input signal in response to a control signal whereby the value of said input signal is dependent on the value of said control signal, and frequency stabilization means for stabilizing the frequency of operation of said oscillator; said frequency stabilization means comprising first signal producing means connected to said element for applying a first signal to said element which is proportional to said modulating signal whereby a second signal is developed across said element in response to the application of said first signal thereto, switch means having an input portion connected to said element and being selectively operable to connect said input portion with an output portion whereby said second signal appears at said output portion, a reference signal source, and comparing means connected to said signal generating means, the output portion of said switch means and said reference signal source for producing said control signal in accordance with the difference between said second and reference signals.
Claim 15
Dependent Claim
19 words
A frequency stabilized transmission apparatus as in claim 12, in which said element comprises a limited space-charge accumulation diode.
Claim 16
Dependent Claim
39 words
A frequency stabilized transmission apparatus as in claim 12, in which said reference signal source comprises a variable voltage supply whereby the value of said reference signal may be selectively varied to correspondingly vary the frequency of said oscillator.
Claim 17
Dependent Claim
45 words
A frequency stabilized transmission apparatus as in claim 12, in which said first signal producing means includes a lead connected between said signal generator means and said element and having a resistance therein, whereby said input signal is applied to said element through said resistance.
Claim 18
Dependent Claim
94 words
A frequency stabilized transmission apparatus as in claim 12, in which said element has a threshold voltage and the resonant frequency of said element is dependEnt on the difference between the value of said modulating signal and said threshold voltage, said first signal producing means comprising a source of potential for producing a voltage signal which is proportional to the negative magnitude of said threshold voltage, and a lead connecting said source of potential to said element whereby said first signal is proportional to the difference between said modulating signal and said threshold voltage.
Claim 19
Dependent Claim
85 words
A frequency stabilized transmission apparatus as in claim 16, in which said oscillator includes a parasitic resistance, and a resistor connected in series with said element whereby said first signal is applied across said series resistor and said element, said resistor having a value substantially equal to said parasitic resistance, said switch means including a lead for connecting said sensing means across the series circuit of said element and said resistor whereby said second signal includes the voltage drops across said element and said resistor.
Claim 20
Dependent Claim
44 words
A frequency stabilized transmission apparatus as in claim 12, in which said second signal is a DC signal, and said switch means comprises a switch connected with said modulator and responsive to the absence of said modulating signal for passing only said second signal.
Claim 21
Dependent Claim
54 words
A frequency stabilized transmission apparatus as in claim 12, in which said second signal is an AC signal, and said switch means is connected with said modulator to pass said second signal only when said modulating signal is not present, and said reference signal source comprises an AC source synchronized with said AC signal.
Claim 22
Dependent Claim
25 words
A frequency stabilized transmission apparatus as in claim 12, and clipping means connected to said modulator for clipping said modulating signal above a preselected level.
Claim 23
Dependent Claim
44 words
A frequency stabilized transmission apparatus as in claim 20, in which the resistance of said oscillator changes during the application of said modulating signal, and predistortion means connected to said modulator for predistorting said modulating signal in inverse relationship to said change in resistance.
Claim 24
Dependent Claim
31 words
A frequency stabilized transmission system as in claim 21, in which said predistortion means comprises the parallel circuit of a capacitor and a resistor connected between said modulator and said oscillator.
Claim 25
Dependent Claim
186 words
A frequency stabilization system for stabilizing the frequency of a circuit containing an element whose frequency varies in accordance with the relationship (Rf + Rp) (2 Vb -Vth) wherein: Rf is the low field resistance of the element; Rp is the parasitic resistance of the circuit; Vth is the threshold voltage of the element; and Vb is the bias voltage applied to said element comprising first signal means for producing a first signal proportional to the difference between said bias and threshold voltages, a lead connecting said first signal means with said element to apply said first signal thereto whereby a second signal is developed across said element which is proportional to the product of said low field resistance and said first signal, switch means having an input portion connected to said element and being selectively operable to connect said input with an output portion whereby said second signal appears at said output portion and bias varying means connected to the output portion of said switch means for varying the bias voltage applied to said element until said relationship is substantially equal to a preselected constant.
Claim 26
Dependent Claim
186 words
A frequency stabilization system for stabilizing the frequency of a circuit containing an element whose frequency varies in accordance with the relationship (Rf + Rp) (2 Vb -Vth) wherein: Rf is the low field resistance of the element; Rp is the parasitic resistance of the circuit; Vth is the threshold voltage of the element; and Vb is the bias voltage applied to said element comprising first signal means for producing a first signal proportional to the difference between said bias and threshold voltages, a lead connecting said first signal means with said element to apply said first signal thereto whereby a second signal is developed across said element which is proportional to the product of said low field resistance and said first signal, switch means having an input portion connected to said element and being selectively operable to connect said input with an output portion whereby said second signal appears at said output portion and bias varying means connected to the output portion of said switch means for varying the bias voltage applied to said element until said relationship is substantially equal to a preselected constant.
Claim 27
Dependent Claim
71 words
A frequency stabilization system as in claim 23, and a resistor connected in series with said first signal means and said element and having a resistance substantially equal to said parasitic resistance, said switch means comprising a lead connecting said switch means across said resistor and said element, whereby said second signal is proportional to the product of the sum of said resistor and loW field resistance and said first signal.
Claim 28
Dependent Claim
83 words
A frequency stabilization system as in claim 23, in which said bias varying means comprises first means for applying said bias voltage to said element in response to a control signal, a reference signal source for producing a reference signal proportional to said preselected constant, comparing means for comparing said reference and second signals and for producing said control signal in accordance with the difference therebetween, and a lead connecting said control means to said first means to apply said control signal thereto.
Claim 29
Dependent Claim
53 words
A frequency stabilization system as in claim 23, in which said low field resistance changes during the application of said bias voltage to said element, and predistortion means connected to said element for changing said bias voltage inversely to said change in low field resistance to maintain said relationship equal to said constant.
Claim 30
Independent Claim
134 words
A method of stabilizing the frequency of a transmitter of the type comprising: an oscillator having an active element the resonant frequency of which varies as a function of at least the resistance of said element and the value of a biasing signal applied to said element, control means responsive to a control signal for producing said biasing signal the value of which is dependent on the value of said control signal, and a lead connecting said element and control means, said method comprising producing a first signal which is proportional to said biasing signal, applying said first signal to said element to produce a second signal in response thereto, comparing said second signal with a reference signal, and producing said control signal in accordance with the difference between said second and reference signals.
Claim 31
Independent Claim
134 words
A method of stabilizing the frequency of a transmitter of the type comprising: an oscillator having an active element the resonant frequency of which varies as a function of at least the resistance of said element and the value of a biasing signal applied to said element, control means responsive to a control signal for producing said biasing signal the value of which is dependent on the value of said control signal, and a lead connecting said element and control means, said method comprising producing a first signal which is proportional to said biasing signal, applying said first signal to said element to produce a second signal in response thereto, comparing said second signal with a reference signal, and producing said control signal in accordance with the difference between said second and reference signals.
Claim 32
Dependent Claim
26 words
The method of claim 27, including the step of changing the value of reference signal to produce a corresponding change in the frequency of said element.
Claim 33
Dependent Claim
57 words
The method of claim 27, wherein the element has a threshold voltage and the resonant frequency of the element is proportional to the difference between the value of the biasing signal and said threshold voltage, said method comprising the steps of making said first signal proportional to the difference between said biasing signal and said threshold voltage.
Claim 34
Dependent Claim
17 words
The method of claim 27, including the step of clipping the biasing signal above a preselected level.
Claim 35
Dependent Claim
41 words
The method of claim 27, in which the resistance of said element varies as said biasing signal is applied to said element, said method including the step of varying said biasing signal to eliminate the effects of said variations in resistance.
Claim 36
Dependent Claim
122 words
Apparatus for stabilizing the frequency of the transmitter of the type having an oscillator having an active element the frequency of which varies as a function of the resistance of the element and the value of a modulating signal applied to said element and wherein the resistance of said oscillator changes during the application of said modulating signal; said apparatus comprising predistortion means for predistorting said modulating signal in inverse relationship to said change in resistance, said predistortion means comprising limiting means for limiting the maximum amplitude of said modulating signal to preselected level, and waveform varying means for changing the waveform of said modulating signal to produce a modulating signal which slopes in a direction opposite to said change in resistance.
Claim 37
Dependent Claim
122 words
Apparatus for stabilizing the frequency of the transmitter of the type having an oscillator having an active element the frequency of which varies as a function of the resistance of the element and the value of a modulating signal applied to said element and wherein the resistance of said oscillator changes during the application of said modulating signal; said apparatus comprising predistortion means for predistorting said modulating signal in inverse relationship to said change in resistance, said predistortion means comprising limiting means for limiting the maximum amplitude of said modulating signal to preselected level, and waveform varying means for changing the waveform of said modulating signal to produce a modulating signal which slopes in a direction opposite to said change in resistance.
Claim 38
Dependent Claim
18 words
Apparatus as in claim 32, in which said limiting means comprising clipping means for clipping said modulating signal.
Claim 39
Dependent Claim
50 words
Apparatus as in claim 33, in which said clipping means comprises a voltage source, and a unidirectional current conducting device adapted to be connected between a modulating signal source and said voltage source and polarized to conduct current when the amplitude of said modulating signal rises above said voltage source.
Claim 40
Dependent Claim
32 words
Apparatus as in claim 33, in which said waveform varying means comprises the parallel connection of a resistor and a capaciTor adapted to be connected between said limiting means and said element.
Claim 41
Dependent Claim
32 words
Apparatus as in claim 34, in which said waveform varying means comprises the parallel connection of an inductor and a resistor connected between said unidirectional current conducting device and said voltage source.
Claim 42
Dependent Claim
32 words
Apparatus as in claim 34, in which said waveform varying means comprises a sawtooth voltage generator connected to said voltage source and responsive to said modulating signal for producing a sawtooth signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-14 | 1976-11-13 | 1977-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-14 | 1980-11-13 | 1981-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-14 | 1984-11-13 | 1985-05-15 | $7700.00 | Window Closed / Lapsed |